This proposal is designed to test the hypothesis that cocaine and the newly described cocaine-alcohol metabolite, cocaethylene, have synergistic effects on HIV infection in vivo and in vitro. This proposal capitalizes on the high incidence of cocaine use and AIDS in Dade County, Florida. The cohort for the proposed studies will be selected from the Miami Outreach Project, a study designed to determine the extent and risk of HIV infection associated with crack cocaine use. Ongoing epidemiological studies of crack cocaine and HIV in Miami currently assess the history, nature, frequency and social context of drug use and sexual behaviors. The increased incidence and progression of AIDS in drug users may result from a number of different factors, including 1.) needle sharing, 2.) multiple sexual partners, 3.) drug-induced impairment of the immune system, and 4.) activation of HIV-1 by co-infection with HTLV-I or II. This proposal seeks funds to provide evidence for a direct action of cocaine and cocaethylene on HIV expression, infectivity and replication. Using a standardized interview instrument, 100 African-American women, who are HIV seropositive, will be divided into two subgroups based on the frequency of cocaine use: 1.) cocaine users with elevated cocaine/cocaethylene and 2.) subjects who are very infrequent users with low to negligible levels of these compounds. Detection of drug and metabolite levels will be confirmed in toxicology screens by GC/MS analysis. Virus load will be determined in plasma and PBMNCs obtained from these subjects to determine if there is increased virus replication associated with specific drug use patterns. Bioprofile studies using HIV-1 isolated from blood lymphocytes and monocyte/macrophages will determine the influence of drug use on tropisms of the isolates. A comparison of the virulence of the HIV-1 isolates and stimulatory effects of cocaine, cocaethylene, and ethanol on HIV replication in these cells will also be determined. Statistical analysis will assess the effects of drug use frequency, route of administration (IV vs. non-IV), and numbers of sexual partners on virus load, bioprofile, and disease progression. The effects of the cocaine and cocaethylene on different phases of the virus life cycle including expression, virus production, assembly, infectivity, and tropism will be evaluated in molecular viral studies. Using a uniquely developed recombinant pseudovirus system with envelope sequences derived from HIV isolated from the drug users, the direct effects of cocaine and cocaethylene on the phases of HIV replication will be assessed.